/* boot.S - bootstrap the kernel */
/* Copyright (C) 1999, 2001  Free Software Foundation, Inc.

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */

#define ASM_FILE        1
#include "multiboot.h"

/* C symbol format. HAVE_ASM_USCORE is defined by configure. */
#ifdef HAVE_ASM_USCORE
# define EXT_C(sym)                     _ ## sym
#else
# define EXT_C(sym)                     sym
#endif

/* The size of our stack (16KB). */
#define STACK_SIZE                      0x4000

/* The flags for the Multiboot header. */
#ifdef __ELF__
# define MULTIBOOT_HEADER_FLAGS         0x00000003
#else
# define MULTIBOOT_HEADER_FLAGS         0x00010003
#endif

.text

.globl start, _start
start:
_start:
jmp multiboot_entry

/* Align 32 bits boundary. */
.align 4

/* Multiboot header. */
multiboot_header:
/* magic */
.long MULTIBOOT_HEADER_MAGIC
/* flags */
.long MULTIBOOT_HEADER_FLAGS
/* checksum */
.long -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
#ifndef __ELF__
/* header_addr */
.long multiboot_header
/* load_addr */
.long _start
/* load_end_addr */
.long _edata
/* bss_end_addr */
.long _end
/* entry_addr */
.long multiboot_entry
#endif /* ! __ELF__ */

multiboot_entry:
/* Initialize the stack pointer. */
movl $(stack + STACK_SIZE), %esp

/* Reset EFLAGS. */
pushl $0
popf

/* Push the pointer to the Multiboot information structure. */
pushl %ebx
/* Push the magic value. */
pushl %eax

/* Now enter the C main function... */
call EXT_C(cmain)

/* Halt. */
pushl $halt_message
call EXT_C(printf)

loop: hlt
jmp loop

halt_message:
.asciz "\nSistema Interrompido!"

/* Our stack area. */
.comm stack, STACK_SIZE
